It’s taken over two decades for Orson Scott Card’s classic sci-fi novel Ender’s Game to make it to the big screen, but all the built-up anticipation didn’t lead to out-of-this-world box office numbers. The film adaptation debuted with $28 million from 3,407 theaters on its first weekend – a start in the same range as Will Smith’s misfire After Earth, which opened with $27.5 million earlier this year. Summit and OddLot Entertainment spent $110 million on the space adventure starring Asa Butterfield and Harrison Ford, but Ender’s Game will need great legs domestically and strong returns overseas to justify its cost (and any potential sequels).

Of course, the film didn’t bomb the way other YA-adaptations like The Host, Beautiful Creatures, or The Mortal Instruments: City of Bones have recently, but its opening was nowhere near the debuts of Twilight or Hunger Games, both of which had less expensive first editions than Ender’s Game. Notably, both of those films targeted young women primarily, while Ender’s Game’s audience was 58 percent male and 54 percent above the age of 25. Crowds issued the film an average “B+” CinemaScore grade.

Jackass Presents: Bad Grandpaheld up very nicely in second place, dropping just 36 percent to $20.5 million. That is by far the smallest second-weekend drop for any of the Jackass films, and it gives Paramount’s $15 million prank comedy $62.1 million total after ten days. If Bad Grandpa continues to maintain great holds at the box office, it could exceed $100 million total. Take that, Oscar season!

Third place belonged to CBS Films’ Last Vegas, which opened with $16.5 million in 3,065 theaters. The film, which stars Morgan Freeman, Robert DeNiro, and Michael Douglas, opened ahead of last year’s Hope Springs, another film targeting the oft-ignored 45+ demographic, which started with $14.7 million on the way to $63.5 million total. Thanks strong word-of-mouth and an “A-” CinemaScore grade, older audiences may flock to the theater gradually over the next few weeks and push Vegas’ total as high as $60 million. For a humble $28 million comedy, that’s a lot like hitting the jackpot.

Free Birds started in fourth place with $16.2 million, and though the film wasn’t a total turkey, its box office left a lot to be desired. Relativity’s $55 million animated entry, which features the voice of Amy Poehler, opened in an ultra-wide 3,736 theaters with virtually no family competition (Cloudy With a Chance of Meatballs 2 arrived six weeks ago), but it could only muster a $4,336 per theater average. On the bright side, Free Birds did spike 82 percent from Friday to Saturday, which suggests that it is playing well with young tots during matinee shows, and it should hold up well as Thanksgiving approaches – especially with an “A-” CinemaScore. It may earn back its budget yet.

Rounding out the Top 5 wasGravity, which pulled in another $13.1 million in its fifth weekend. Warner Bros.’ $100 million space drama starring Sandra Bullock and George Clooney has now earned $219.1 million total and, with a little awards attention, should ultimately hit about $250 million domestically.

Outside the Top 5, 12 Years A Slave continued its successful expansion this weekend. The Oscar contender jumped from 123 theaters into 410 locations and pulled in $4.6 million as a result. That gave the film an excellent $11,220 venue average, thus assuring it will continue to expand into more markets in the near future. Fox Searchlight could have a sleeper hit on their hands.

On the international front, Thor: The Dark World hammered up a great debut this weekend. The film pulled in $109.4 million from 36 territories, which represents about 70 percent of the international market. The film performed best in the United Kingdom ($13.4 million), France ($9.4 million), and Mexico ($8.2 million), and it still has openings in China and Japan to look forward to. The original Thor grossed $268.3 million internationally in 2011, but after a major exposure-boost from The Avengers, The Dark World seems poised to easily outdo that film’s overall performance. It opens in the U.S. on Friday.